In today's mobile networks, a mobile terminal such as a smart phone, tablet, smart watch, laptop, etc., commonly referred to as User Equipment (UE) may be either in idle or in connected mode as described e.g. in 3rd Generation Partnership Project (3GPP) specification TS 23.401. Briefly described, when the UE is in connected mode, it is able to send and receive user plane data packets.
In connected mode, the network and the UE have established a radio connection, and the network has reserved resources for the UE. For example, the base station, referred to as an Evolved NodeB (eNodeB), located in an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) of a Long-Term Evolution (LTE) technology communications network, holds UE associations referred to as “UE context” including for instance radio bearer configuration, encryption keys, transport tunnel identifiers, data buffers, etc.
In idle mode, the UE cannot send or receive user plane data packets as network resources for the UE are kept to a minimum. The eNodeB holds no UE context at all, and control signalling between UE and network is kept to a minimum, which saves UE battery consumption.
In the concept of Mobile Service Chaining, Software Data Network (SDN) technology is utilized to intelligently chain service functions so that traffic from each subscriber only traverses a particular set of service functions as defined by a policy for a particular subscriber. For example, an operator can configure a service chaining policy such that only web traffic is sent to a content optimization service.
With Mobile Service Chaining, the traffic path for any arbitrary flow or aggregate of flows can be dynamically changed by simply changing the policy associated with that flow in that an SDN controller automatically programs routers, switches and application servers in the network.
However, in Mobile Service Chaining, the process of switching between idle and connect mode is not applied; rather, the UE is always considered to be connected in Mobile Service Chaining.